A Light Detection and Ranging (LiDAR) system is used to determine distances between the system and objects or ground by sending out light energy (laser beams) which may be a pulsed or a continuous wave which are reflected back to a sensor of the system. By measuring how long it takes for the signals to return, the LiDAR measures the distance to the object or ground in a hard target system or to atmospheric condition in a soft target system. The strength of LiDAR returns varies with the strength of the generated laser beam and the composition of the surface object reflecting the return. The reflective percentages are referred to as LiDAR intensity. A number of factors affect the LiDAR intensity including range, incident angle, receiver and surface composition.
Different type of LiDAR applications use different wavelength laser beams. For example, ground based systems typically use wavelengths in the 500-600 nm range while air based systems typically use wavelengths in the 1000-1600 nm ranges. The smaller wave lengths are good for detecting small objects while the larger wavelengths are good for penetrating clouds.
One safety concern with the use of LiDAR is that the light energy that is generated by the LiDAR may cause permanent damage to an eye of an individual the pulsed light energy is incident upon. Eye damage is typically damage to the retina of the eye in the form of burns. The potential to cause harm is directly proportional the strength of the pulsed light energy and the wavelength.